Today, many wireless communication techniques are being proposed to achieve a high-speed mobile communication. Among them, an Orthogonal Frequency Division Multiplexing (OFDM) scheme is accepted as one of the most promising techniques for a next generation wireless communication. The OFDM scheme is expected to be widely used in the future wireless communication techniques, and currently is used as a standard in the Institute of Electrical and Electronics Engineers (IEEE) 802.16-based Wireless Metropolitan Area Network (WMAN) referred to as the 3.5 generation technology.
Meanwhile, the wireless communication systems are evolving to provide a high-speed data service in comparison with a legacy system or to address an implementation issue. In such a system evolution process, various systems may coexist in the same area according to a degree of compatibility with the legacy system. For example, a new system may be installed in an area where an IEEE 802.16e system exists. In this case, the new system has to be able to provide services not only to a legacy Mobile Station (MS) but also to a new MS.
A currently used OFDM-based broadband wireless communication system has a structure wherein only an MS using a single bandwidth can be supported using one Frequency Allocation (FA). Therefore, to support a new MS, using a wider bandwidth to be developed in the future, an FA of the system has to be changed to a new FA having a bandwidth corresponding to the wider bandwidth used by the new MS. However, due to the change of the FA, the system cannot provide a service to a legacy MS using a narrow bandwidth. That is, there is a problem in that all legacy MSs have to be changed while changing the FA of the system. Accordingly, there is a need for a method of supporting both a legacy MS, using a narrow bandwidth, and a new MS, using a wide bandwidth, in an evolution process of a broadband wireless communication system.